The present invention relates to a technique for determining a combination of links to be used by a node coupled to a plurality of links.
The appearance of Next Generation Networks (hereinafter referred to as NGNs) and a variety of wireless communication services has increased options of links of Wide Area Networks (hereinafter referred to as WANs). Especially, companies contract with a network operator to use plural types of WAN links so that communication is enabled over these links (hereinafter, this is referred to as a multi-home environment). Thereby, communication is maintained even in case a failure occurs in a particular WAN link and availability is enhanced.
On the other hand, network operators providing communication services contract with users to provide a comprehensive service involving new networks coming up one after another in a form that physical networks are concealed, instead of providing each of the new networks upon its coming up as a new service to users. In this way, by early provision of a new, less-costly, high-function network to users, the network operators are achieving operation cost reduction. Consequently, users can make use of a latest network as a high-speed, large-capacity, and stable network early without being aware of new network services coming up one after another.
In such circumstances, techniques for improving communication performance by making effective use of a plurality of WAN links in the multi-home environment are developed. For example, U.S. Pat. No. 6,665,702 discloses a technique for providing communication over an optimum route in response to a communication access request from a client. This technique measures communications between a gateway that couples to a plurality of WAN links and a server and determines an optimal route based on information such as delay time and the number of hops, without using a predetermined main link and sub-link statically.